Activity 90-Figuring out Fossils
Learning Target:
We will observe fossil evidence of creatures that lived in the past.
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Pre-Lab:
Read page F-11 and answer the following questions:
1. What is the name of the planet’s thin outer layer? _the
crust________________________
a. How big is this layer? _40 km thick (approx. 25 miles) _____________________
b. What is this layer made of? _many layers of rock ___________________________
c. What are three ways this layer can form?
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__volcanic eruptions and lava _______________________________________
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__floods spread mud or sand ________________________________________
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__sediments (sand, dirt, mud) collect on lake or ocean floors __________
______heat & pressure underground _______________________________________
2. New layers of rock _____seal __ __off____ the layer below it.
3. _Organisms______ trapped within these sealed off layers can become part of the __ rock_____
itself.
4. Any trace of life preserved in a rock it is called a _____________fossil________________. It can be
an _entire_ organism, a ____part____ of an organism, a ______footprint______, a piece of
feces or a piece of ____shell________, ____bone______ or __tooth_____.
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Lab: Complete the data table below:
Fossil Name
(Genus)
Goniobasis
Sketch
Observations (for example,
“looks like a clam shell”)
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Knightia
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Admetopsis
Ammonite
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Compressed spiral
shells, cone-shaped
Like a snail
Mottled brown and
tan
0.6 cm (6 mm) length
0.4 (4 mm) wide
Small, bony fish
Brown fossils in tan
sediment
4 cm (40 mm) long
1.6 (16 mm) wide
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Spiral shell, cone
shaped
Like a snail
1.8 cm (18 mm) long
1.1 cm (11 mm) wide
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Spiral shell
Black rock
Like a nautilus
1.0 cm (10 mm) long
0.7 cm (7 mm) wide
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Alethopteris
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Dark gray rosk strata
wit light gray fossils
Multiple leaves
Central branch
Like a fern
Leaf: 1.5 cm (15 mm)
long
0.5 cm (5 mm) wide
Tabulopyllum
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Conical
Tooth-like structure
1.4 cm (14 mm) long
0.7 cm (7 mm) wide
Mucrospirifer
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Triangular shape
Two-sided like a clam
(bivalve)
Yellow-tan color
1.7 cm (17 mm) long
2.8 cm (28 mm) wide
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Elrathi
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Black rock
Shell structure
Looks like a Horseshoe crab
2.2 cm (22 mm) long
1.9 cm (19 mm) wide
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Analysis:
1.
Review your notes on the eight different types of fossils. Do you think any of them are from similar species?
Explain, using evidence from this activity to support your answer.
Goniobasis and Admetopsis look
like shellfish (mollusks), therefore are related. No other organisms appear to be
related
2.
In this activity, you were given a fossil to examine. What additional observations could you have made about
the fossil if you had discovered it yourself?
Your observations should include:
 Observe its surroundings (rocky type, age, aquatic or land)
 Observe other fossils around (live in groups, what it ate)
3. Choose one of the eight fossils you examined.
a. Based on the fossil, describe what you think this organism looked like when it was alive. Include your
evidence for your description. _Answers will vary. A complete answer includes
specific
SIZE (measurements), SHAPE. __________________________________________________
b. In what type of environment would you expect to find this organism? Explain your reasoning. _
Answers will vary. A complete answer includes general HABITAT (ocean or land)
and LOCATION (deep water, shallow water, shores, fresh water, beach,
wetlands, plains, mountains.) ___________________________________________________
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4. Although you probably have a vivid picture of dinosaurs in your mind, no one has ever seen a living dinosaur. All
the evidence for the existence of dinosaurs comes from fossils.
a. What details about the appearance and behavior of dinosaurs do you think would be easiest to
determine from fossils? Why?
Bones can provide very good evidence for overall size,
shape, and means of locomotion (movement). Teeth can tell about feeding
habits.
b. What details about the appearance and behavior of dinosaurs do you think would be hardest to
determine from fossils? Why?
Physical traits like skin color/texture are the hardest to
determine, because such tissues rarely fossilize. Physiological traits (like warm
vs. cold blooded) and behavioral traits (social interactions) are also difficult.
FOSSIL FORMATION NOTES:
Two types of fossil formation:
1. Remains- parts that don’t decompose.
a. Teeth, shells, skulls and skeletons
2. Trace fossils—no actual remains left.
a. Tracks, trails, burrows, borings, nests, coprolite (dino poo)
Two ways of fossil remains:
1. Unaltered- the fossil retains the organisms’ orginal structure and composition
a. Mummification: air-drying and the shriveling of soft body parts before
it becomes buried or frozen.
2. Altered- fossils that have been changed structurally or chemically.
a. Minerals come in and replace the pores and cavities of organism’s bones, teeth
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